This document discusses digital steganography, which is the process of hiding secret information within other non-secret files like images, text, audio, or video. It describes the history of steganography and some common techniques used, such as least significant bit modification in images and altering text features. The document also compares steganography to cryptography and digital watermarking, outlines some types and uses of steganography, and discusses steganalysis and the future of the field.

1. Digital
Steganography
Nikunj Dhameliya
Student @ gvp

2. Outline
 What is Steganography?
 Uses of Steganography
 Its Relation to Cryptography
 Digital Watermarking
 Network Security and Steganography
 Types of Steganography
 Detecting Steganography: Steganalysis
 Future of Steganography

3. What is Steganography?
 The word 'Steganography' comes from greek words
steganos and graphein.
 It combination of two words:
 steganos: covered,protected,secret
 graphy: writing
 Definition:
''The Process of concealing messages or information within
other non-secret text or data''

4. History of Steganography
 The first record uses of steganography can be
tracked back to 440 B.C when Herodotus menssion
two example in his histories.
 World War II the french Resistence send message
on back of curriers in invisible ink.
 World War II Germany use microdots
 Modern Steganography - 1985, with the
development of personal computers
 Digital Steganography – with internet

5. Uses of Steganography
 Governments
 Businesses: Digital Watermarking
 Individuals

6. Steganography & Cryptography
 Steganography and Cryptography are closely related
 The difference is in their goals...
– Cryptography: although encypted and
unreadable, the existence of data is not hidden
– Steganography: no knowledge of the existence of
the data
 Steganography and Cryptography can be used
together to produce better protection

7. Digital Watermarking
Image “painted” with the watermark: “Invisible Man” © 1997, Neil F.
Johnson

8. Digital Watermarking
 Used primarily for identification
 Embedding a unique piece of information within a
medium (typically an image) without noticeably
altering the medium
 Almost impossible to remove without seriously
degrading an image

9. Digital Steganogaphy & Watermarking
 Digital watermarking hides data in a file, and the act
of hiding data makes it a form or steganography
 The key difference is their goals...
– Steganography: hiding information
– Watermarking: extending the file with extra
information
 Steganographic information must never be apparent
to a viewer unaware of its presence.

10. Network Security and Steganography
 Confidentiality: any unauthorized person does
not know that sensitive data exists
 Survivability: verifying that the data does not get
destroyed in the transmission
 No detection: cannot be easily found out that the
data is hidden in a given file
 Visibility: people cannot see any visible changes
to the file in which the data is hidden

11. Types of Digital Steganography
 Hiding a Message inside Text
 Hiding a Message inside Images
– Most popular technique
 Hiding a Message inside Audio and Video
Files

12. Hiding a Message inside Text
 Partially effective
randoM capitalosis is a rarE disEase ofTen
contrAcTed by careless inTernet users. tHis sad
illnEss causes the aFfected peRsON To randomly
capitalize letters in a bOdy oF texT. please
do not confuse this disease witH a blatant
attEmpt aT steganogRAPhy.
Reveals: MEET AT THE FRONT OF THE TRAP

13. Hiding a Message inside Text
 First-letter algorithm
 Every n-th character
 Altering the amount of whitespace
 Using a publicly available cover source

14. Hiding a Message inside Images
 The most popular medium!
 Least-significant bit (LSB) modifications
– 24-bit vs. 8-bit images
– Tools to implement LSB: EzStego and S-Tools
 Masking and Filtering
 Algorithms and Transformations

15. Hiding an Image within an Image
Removing all but the two least significant bits of each color
component produces an almost completely black image. Making
that image 85 times brighter produces the image below
source: wikipedia.org

16. Hiding a Message inside Audio or
Videos Files
 Advantages
– Human limitations – 20.000 Hz.
– Large amount of data that can be hidden inside
– Hard to recognize because of the continuous flow
of information (moving stream of images and
sound)

17. Steganalysis
 Detecting and decoding the hidden data
within a given medium
 Even if secret content is not revealed,
modifying the cover medium changes the
medium’s statistical properties
 Distributed Dictionary Attack

18. Advantage
 It is used to combine any format of message
to image.
 Peer to peer private communication.
 Posting secret communication on web to
avoid transmission.
 Maintaining anonymity.

19. Disadvantage
 Someone else with a steganography
detection and cracking tool could expose the
message.
 Better to understand use of standardized
encryption.

20. Future of Steganography
 The most important use of steganographic
techniques will probably lie in the field of
digital watermarking
 Might become limited under laws -
governments claimed that criminals use
steganography to communicate
...the End